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forum forum Technical Cough/Hiccup/Hesitation at low/mid Throttle

This topic contains 13 replies, has 6 voices, and was last updated by David Q David Q 1 week ago.

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  • #13143
    David Q
    David Q
    Participant

      I’ve been meaning to ask the forum about this for ages, but the impending 40th anniversary meeting has finally prompted me to send this in the hope that someone there or on the forum says “Oh, you need to adjust the thingumijig to 1.237 xyzzy”.

      At low to medium throttle my 2000 California (electronic injection) engine has an intermittent cough/hiccup/hesitation, which gets worse as the engine gets hotter (particularly when the air temperature is higher). I’ve been to a local Moto-Guzzi workshop and they’ve done a complete diagnostic on the ECU. Their first diagnosis was that I’ve failed to grease the shaft of the throttle flap that measures the throttle opening – does that make sense? It’s my attempted translation from the German original. He said that he had spare, but unfortunately had just promised it to another customer. If I could live with it, I should return after my recent visit to Scotland. In fact it wasn’t too bad there since it was relatively cool (about 16 deg max). However, at a local Oldtimer replica meeting near here where it was a lot hotter, several people commented on the cough. I therefore took the car back to my friendly dealer, and said that it appeared to be worse at higher air temperatures. He discovered another throttle in his workshop, and waggled that, comparing it with mine and came to the conclusion that his diagnosis wasn’t correct, since that shouldn’t have been worse as a function of temperature. He then made some adjustments to the throttle bodies, and said to try that. His new diagnosis was that the air filters (which had just been cleaned at there first visit) were too small, resulting in back pressure, and that I should try to get some other, larger ones. He recommended K&N RC-1822, which I ordered. They’ve just arrived and I discovered that they are identical to those that were originally fitted. I’ve switched to them anyway, just in case there was some difference in back pressure, but with no change.

      Anyone got any suggestions?

      Looking forwards to meeting many of you in just a couple of days.

      David Q

    • #13144
      david
      david
      Participant

        Hi David, my 2001 1100 Injection tends to spit back through the filters occasionally .I moved the small red temperature sensor which was under the bonnet by the injector linkages forwards to just under the nose of the bonnet..-seemed the bike had it placed forwards..when I looked around a guzzi dealers.
        the coughing might be more apparent as there is no big joint air filter to absorb it..?

      • #13145
        David Q
        David Q
        Participant

          Hi David, Many thanks for the suggestion. My temperature sensor is on the right hand side of the throttle assembly, right behind the RHS cylinder head, so it might well be getting bad readings. I’ve just moved it to just under the oil catchment thingy (or whatever it’s called) in the V of the engine block, attached by tie wraps to the central hose. Not terribly elegant, but it’ll do for now, and I’ll replace it with something more permanent if it does indeed improve things. A quick 30min ride around here shows that it’s not solved the problem entirely, but I could convince myself that things seem a bit better. Would the ECU need to be re-calibrated in order to make a real check?

          Anyway, thanks again for the suggestion!

          I didn’t notice your name in the Forum thread about the 40th Anniversary meeting so don’t know whether you’ll be there. Hopefully I’ll be able to chat to you.

          David Q

        • #13146
          SteveO
          SteveO
          Participant

            David Q
            Have you checked for inlet air leaks. Certainly a source of hesitation and coughing on Harleys. Might be worth comparing spark plug colour. Best way is to drive it towards home and when close enough switch off the engine whilst still on the throttle and coast to a stop. Colour should be tan to grey. A sooty thread with tan electrodes is fine. If plugs look reasonable and the ecu and throttle bodies have been checked out as OK not sure where to look. I get a pop back now and again when hot, but I know that is an exhaust leak which I will not seal until I have done some other things.
            By the way enjoyed your build notes and photos when I was overseas working.

            Steve

          • #13148
            WestEndGuzzi
            WestEndGuzzi
            Keymaster

              Hello David
              I’m no expert on efi systems but do think that an ambient temperature sensor should do that. Not be influenced by direct sunlight or heat from the air cooled engine. Move it to a shady spot.

              Best solution is to convert the engine to carburettor aspiration. (as I did with Edith)
              The owner driver can adjust it. You don’t have to take it to a technician who, help, can’t correct a problem, as you the owner can’t.

              For the price of a pair of PHF36 Dellorto carbs and an electronic ignition sytem, you could be in charge of that cough.

              Debate needed at the weekend.

              You, David, have put a great effort into recording your build for us all to see. Thank you

              Next proposal, T4 on carbs.

              Tony

            • #13149
              Richard and Pat
              Richard and Pat
              Participant

                Only tinkers convert a perfectly good system to carbs; they are worse than looking after someone else’s dog!

                • #13155
                  WestEndGuzzi
                  WestEndGuzzi
                  Keymaster

                    Richard

                    As you have brought up the dog analogy, we have just had 2 dogs to stay while owners were on holiday.
                    A shih tzu / bichon bitch (we’ll call that the EFI model) and a staffy cross dog (the CARB model)

                    The EFI was a total pain, barked at everything, out of control, all over furniture, would not eat dog food, would not sleep anywhere unless on a proper bed with a person in it. Had to send it to granddaughters at night, she allows such behaviour. There was no controlling, glad to get rid of it yesterday.

                    The CARB was a joy to have. Obedient, responsive, adjusted to our home and life style, ate dog food, slept soundly in his bed. Very controllable, if he was told to get out of the sun, he went in the shade. Sorry to see him taken away.

                    I beg to inform you that tinkers are a talented line of artisans that can make useful items from raw materials, without any help from programmable logic controllers.
                    Is there an app for fixing a leak in a petrol tank?

                    I rest my case.

                • #13150
                  David Q
                  David Q
                  Participant

                    Replying to all who posted to the thread:-
                    Steve: Thanks for the suggestions, which I’ll have to defer until after the 40th anniversary meeting, but will certainly follow up on!
                    Tony: Hmm, I think you have an unwarranted expectation about my technical/mechanical ability! I spent 40 years working with computers and have absolutely no aptitude for mechanical things involving sensitive fingers tweaking things. I greatly exceeded my own expectations by getting Bluebelle on the road and daily expect her to fall apart around me, leaving me like Toad of Toad Hall, clutching the steering wheel and making feeble “brum, brum…” sounds.
                    Richard and Tony: I look forwards to a lively discussion on this topic at the weekend!
                    I’m glad that people found my photos useful – I missed the fact that they were no longer available and will try to follow up…
                    David Q

                  • #13151

                    peakrock
                    Participant

                      Hi David, my Triking has the 1100 EFI engine, standard ECU and K & N filters. I mounted my temperature sensor on a small hanging bracket in the middle of the transmission tunnel so it’s about 2 or 3 inches behind the ends of the filters, reasoning was that it would measure the actual air temperature as it entered the injection system, so the ECU could adjust accordingly. Sometimes when slowing down on a long overrun, I get a spitback when I blip the throttle to change down but otherwise no coughing/hesitation etc.

                      I have actually built the Jeffries ECU as well so that I could opimise the fuel mapping to the engine but I haven’t got round to fully sorting it out yet as the Triking runs well enough on the standard ECU. I’ll be at the 40th anniversary this weekend so we could chat and maybe try and bring Tony back to the light… 😉
                      Dave

                    • #13152
                      David Q
                      David Q
                      Participant

                        Hi Dave (there seems to be lots of David/Dave’s on the forum!),
                        Thanks for the feedback. I’ll be interested to see exactly where you mean for the location of the temperature sensor. Let’s get together at the weekend!

                        David Q

                      • #13154
                        David Q
                        David Q
                        Participant

                          As a result of this thread I’ve realised that my build photos were no longer available – and discovered that Richard reported that last year…
                          I’ve moved them to my iCloud and Tony has updated the links.
                          David Q

                        • #13156
                          Richard and Pat
                          Richard and Pat
                          Participant

                            Thank you David and Tony,
                            Being a Tinkerer who can resist the pestilence of carbs forever begging for my attention like an untrained dog unwilling to do your bidding I will need a look at a few of those in the Borcellino build.
                            BTW: I went to a Zoo the other day, all they had to show was one dog. It was a shih tzu.

                          • #13157
                            SteveO
                            SteveO
                            Participant

                              ECUs are great if you can find an app to access the fuel maps as per HD, Triumph etc. If you cannot access then you are at the mercy of a dealer and worse their ability to tune.
                              In such a circumstance I would switch to carbs as suggested. You would still need a decent balancer and say a colour tune or 02 sensor so the cost never stops! The ECU temp sensor could be an issue although I doubt it. If the problem is on both cylinders then much more likely.
                              As well as checking for air leaks I would take a look at the fuel filter (if fitted) if not fitted then I would fit as only a couple of quid.
                              A new set of plugs might be a good investment.
                              Only make one change or adjustment at a time.
                              Steve

                            • #13211
                              David Q
                              David Q
                              Participant

                                Hi Steve,

                                Sorry to have been so long in following up on your suggestions – the 40th anniversary meeting intervened! Anyway, I’ll follow up on your suggestions. I haven’t been able to tell whether one or both cylinders have the problem – it’s too noisy when driving (and I need to act as passenger) and I’ve not managed to induce it when stopped. I’ll certainly follow your suggestion to only do one thing at a time!
                                David

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